DAPD is in the group of anti-HIV drugs known as nucleoside reverse transcriptase inhibitors. Other drugs in this group are ZDV, (AZT), ddI, ddC, d4T and 3TC. DAPD has been tested extensively in the laboratory and in animals. The is the first study in which DAPD will be tested in human subjects. The purpose of this study is to evaluate the safety, tolerance, pharmacokinetics, and antiviral activity of both single and repeat doses of DAPD. The study will also attempt to determine the most effective safe dose of DAPD by testing at least five different doses of the study drug.